@=USER_LOGGED is the ID of the logged in user, so you are getting the correct information. If you want the name of the user, then you need to use the userInfo() function to get that information about the user and pass it in the variables array to the PMFSendMessage() function.

How did you create your @=planDeEstDoc variable? Is it the ID of the Output Document definition?
If you want to attach an Output Document as an attachment to an email, see the programming example for attaching an Output Document file:http://wiki.processmaker.com/3.1/Proces ... sage.28.29